This invention relates generally to the art of endless conveyor belts and more particularly to apparatus for monitoring and maintaining moisture contents of such conveyor belts.
When aggregate material, such as coal, for example, is conveyed on a troughed conveyor belt, a great deal of dust is created which can be both a health hazard and a f ire hazard. In order to reduce this dust, systems have been developed for spraying water onto moving conveyor belts for keeping them and materials transported by them moist, thereby not allowing dust to develop. When such systems are employed, it is undesirable to spray too much water, because this creates unwanted water puddles and sludge which in turn must be cleaned up. For this reason, some such systems which have been suggested have involved monitoring the moisture level of the endless conveyor belts, and/or their contents, for controlling sprayers which spray water onto the belts f or achieving desired moisture-content levels.
Prior art systems which have functioned as described above, have employed various types of sensors for sensing moisture levels of conveyor belts and their contents. However, some of these sensors have not properly functioned within the unfriendly environments of coal mines and coal transporting areas. That is, some such sensors have not been sturdy enough to withstand these unfriendly environments. Also, many such sensors have not been sufficiently accurate. Further, some such sensors have contacted the conveyor belts and in doing so have caused damage to the conveyor belts or, conversely, the conveyor belts have caused damage to the sensors. In this respect, U.S. Pat. No. 4,944,385 to Shelby discloses a particular endless belt moisture control apparatus whose sensors contact conveyor rollers which, in turn, contact a conveyor belt, so that damage to the conveyor belt and to the sensors is effectively avoided.
It is an object of this invention to provide a sensor device for a conveyor-belt moisture control sensor apparatus which is sturdy, accurate, relatively inexpensive and which does not easily damage a conveyor belt nor is easily damaged by the conveyor belt.